// let self = this;

// self.addEventListener('fetch', async (event) => {
//     const {request} = event;
//     let response = await fetch(request);
//     // 3.重新构造Response
//     response = new Response(response.body, response)
//     // 4.篡改响应头
//     response.headers.delete('Content-Security-Policy');
//     response.headers.delete('X-Frame-Options');
  
//     event.respondWith(Promise.resolve(true));
// });